Bulletin d’avalanche

Kootenay Boundary

Jan 10 – 11, 2013Avalanche Canada
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Archivé · expiré 14 years ago

Danger d’avalanche

Sat
Sun
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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Points saillants

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    1–6
    Previously strong winds formed wind slabs that deserve caution and respect.  Wind slabs may be found lower on slopes than you normally see them.

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    Rapid settlement is creating a cohesive storm slab

Confidence

Fair

Weather Forecast

Friday: Light Winds out of North.  Freezing level at valley bottom.  No snow. 1500m temp: -10Saturday: Carbon copy of Friday.  Clear skies, no snow and light northerly winds.Sunday:  High pressure drives a fairly boring weather pattern. Winds bumping up to the bottom end of moderate.  Temps hover around -10 at 1500m

Avalanche Summary

Avalanche activity was widespread on Monday.  Avalanches ran naturally to size 2 and explosives triggered avalanches to size 3.  Crowns ranged from 10 - 60 cm in depth and the bulk of activity involved the January 4th interface.

Snowpack Summary

The recent storm has brought up to 60cm. Consistent SW winds have redistributed the new snow (dramatically in some areas) to create widespread windslabbing on lee and open features in the alpine and exposed treeline. Where the wind has been strongest, windslabs are much lower on slopes than normal.Avalanches have been reported both within the storm layers as well as at the initial storm interface which has been dubbed the January 4th layer. This layer consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds with the facetted snow are improving while the surface hoar &/or sun crust interface is weak. There are reports of Sudden Planar shears (fast & clean) in compression tests and Propagation Likely results in extended column tests on the preserved surface hoar.The midpack is well bonded and strong. The November 28 surface hoar is still being found in isolated, sheltered below treeline locations buried 120cm. The deep crust/facet combo from early November still exists and concern remains (although unlikely) for triggering this layer from a shallow spot or with a heavy load.

Régions couvertes